Microwave electrodynamics of electron-doped cuprate superconductors

We report microwave cavity perturbation measurements of the temperature dependence of the penetration depth, lambda>(*) over bar * (T), and conductivity, sigma>(*) over bar * (T) of Pr2-xCexCuO4-delta (PCCO) crystals, as well as parallel-plate resonator measurements of A(T) in PCCO thin films. Penetration depth measurements are also presented for a Nd2-xCexCuO4-delta (NCCO) crystal. We find that Deltah(T) has a power-law behavior for T < T-c/3, and conclude that the electron-doped cuprate superconductors have nodes in the superconducting gap. Furthermore, using the surface impedance, we have derived the real part of the conductivity, (1)(T), below T-c and found a behavior similar to that observed in hole-doped cuprates.